Dry ice manufacture



Jan. 1, 1963 T. L. UREN 3,070,967

DRY ICE MANUFACTURE Filed Sept. 3. 1959 5 Sheets-Sheet l INVENTOR ATTORNEVS Jan. 1, 1963 T. L. UREN 3,070,967

DRY ICE MANUFACTURE Filed Sept. 3. 1959 3 Sheets-Sheet 2 lA/VENTORATTORN)S.

Jan. 1, 1963 T. L. UREN 3,070,967

DRY ICE MANUFACTURE Filed Sept. 3. 1959 5 Sheets-Sheet 3 254 ENTOR: kilhw B) ATTORNEYS.

ga a ts ilnited This invention relates to Dry Ice manufacture, and moreparticularly to an operation in which snow is formed continuously by theexpansion of liquid carbon dioxide and the snow compacted in Dry Iceblocks.

An object of the invention is to provide a machine and method for thecontinuous forming of CO snow and the compacting of the snow into blocksof varying sizes. A further object is to utilize in such a machine andprocess means for producing a sudden release of the snow to permit itsbeing compacted by compression apparatus, while at the same timeutilizing incoming, relatively warm, liquid CO and returning revert gasformed in the operation to the compressor. A further object is toprovide in such a process and apparatus, effective means for controllingthe formation and release of Snow, the compacting of the snow intoblocks of a desired size, the ejecting of the blocks while still heldunder compression, the control of the return flow of revert gas, andother important steps in the manufacture of Dry Ice. A still furtherobject is to provide a compact machine which may be employed effectivelyfor the production of relative small quantities of Dry Ice as the sameis required, the apparatus being relatively inexpensive and representinga relatively small mass of metal to be cooled in the manufacturingoperation. Other specific objects and advantage; will appear as thespecification proceeds.

The invention is shown, in an illustrative embodiment, by theaccompanying drawings, in which FIG. 1 is a side view in elevation ofapparatus embodying my invention; FIG. 2, an enlarged broken verticalsectional view of the upper portion of the snow tower or column; FIG. 3,a developed perspective view of the compressor piston and associatedparts, the same being shown in spaced-apart relation; FIG. 4, anenlarged vertical sectional view of the snow tower or column and thecompression cylinder communicating therewith; FIG. 5, a transversesectional view taken atthe point of union between the two parts of thesnow tower as indicated by the line 5 of FIG. 4; FIG. 5-A, an enlargeddetail sectional view showing the bottom of the column and tower and thespace therebetween; and FIG. 6, a perspective view of the indicatingmeans employed with the compressor for showing the size of the blockformed in the compression step.

In the illustration given, A designates a snow tower and B a compressioncylinder.

The snow tower, as shown best in FIG. 4, employs a vertical column 10,which may be of relatively uniform diameter. Within the column issupported a coneshaped chamber 11. Both of the cylinders 10 and 11 areseparated at an intermediate point by flanges 12 and 13 and with aclosure plate 14 therebetween. The closure plate 14 has three apertures15 therethrough, each being adjustably controlled by a threaded screw orclosure 16, as shown more clearly in FIG. 5. The purpose of thestructure is to control the flow of gas through the chamber spaceprovided by the cylinders 10 and 11 below the plate 14. As will be laterdescribed, revert gas may pass upwardly through the lower space betweencylinders 10 and 11 and through the apertures 15 into the larger spacebetween the cylinders and above the plate 14, the larger space beingindicated by the numeral 17.

Within the space 17, there is a reverse coil 18 for ates Patent icecarrying liquid CO (usually at a temperature of about 60 F.), the coilpassing downwardly through the cylinder and then being reversed uponitself and extending out of the cylinder through line 19. The inlet tocoil 18 is indicated at 18a and such inlet pipe may extend to anysuitable source of liquid C0 The cooled CO in pipe 19 passes throughcontrol valve 25) on the instrument box 21. On the box 21 may be mountedsuitable guages for indicating the pressure in the snow tower and otherportions of the apparatus and which will aid the operator in theoperation of the machine. When valve 26 is opened, the liquid CO willpass through pipe 22 to the expansion nozzle 23 at the top of the conecylinder 11 controlled by valve 23a. The expansion nozzle or valve maybe of any suitable construction, and is preferably of a type which willgive a nice control of the release of the liquid within cyLnder 11 so asto form snow therein. In the illustration given, the liquid CO isreleased through the valve and discharged through the pipe 24 into thecone 11, which is preferably formed of stainless steel.

I prefer to equip the tower with a safety closure plate 25 which is heldin place by springs 26, as shown more clearly in FIG. 2.

The compression cylinder B comprises preferably a horizontal cylinderhaving centrally thereof an opening 27 communicating with the bottom ofcylinders 10 and 11. The cylinders 10 and 11 are slightly spaced apartat their bottom, preferably by about 5, so as to provide a small orificethrough which revert gases may pass upwardly in the space 28 betweenmembers 10 and 11.

The compression cylinder 13 has a discharge end 29 closed by a movablegate 30 carried by the discharge plunger 31. The plunger 31 engages apiston (not shown) mounted within the hydraulic cylinder 32 to whichpressure fluid is supplied through lines 33 and 34 from the motor-drivenpump 35. Control of the pressure fluid is through a valve 36. Pipe 33 isprovided with a restrictor valve 37 for the purpose of maintainingpressure upon the block of ice while it is being discharged tor alimited period of time.

Opposite the discharge end 2% of cylinder B is mounted the compressorpiston 38. The compressor piston is actuated by the plunger shaft 39which extends through the piston 33 and rearwardly therefrom throughplate 40 and which is connected to a piston (not shown) in the hydrauliccylinder 41. Fluid from the pressure pump 35 is supplied to oppositeends of the cylinder 41 through the pipes 42 and 43, and the flow of thefluid is controlled by the hand valve 44, or, optionally, by thefoot-operated control 45.

The compressor piston 38 may be provided with leathersealing rings 46and at its forward end with a pad 47 formed of leather or other flexibleor resilient material which will retain its resiliency under the intensecold conditions encountered within cylinder A. I have found that leatheris most efiective under these conditions of intense cold, having notendency to stick to the Dry Ice blocks and permitting a ready dischargeof the blocks when formed.

When the liquid CO is expanded, there is formed both snow and revertgases, and the present invention contemplates the return of the revertgases through the chambers 17 and 28 and back to a compressor, and it isdesired to utilize the revert gases in a heat exchange contact with theincoming, relatively warm, liquid CO in the coil 18, while at the sametime raising the temperature of the re vert gases going back to thecompressor. To this end, revert gases are allowed to flow upwardlythrough two separate channels. One channel is through the lower ends ofthe spaced cylinders 19 and 11 and into the space 28 and thence throughthe plate openings into the space 17.

about the cone.

Another channel is upwardly through the forward portion of the cylinderB into communicating boxes 48 and 49 and thence through pipe fit} intothe chamber space 17. Box 48 is in open communication at its bottom withcylinder B and communicates with box 49 through opening 43a. The pipe 54leads from the top of box 49 for carrying revert gases to cylinder space17. I prefer to pass the revert gases through a check valve (not shown)within the box 49 and warm oil returning to the oil reservoir is passedthrough the box 49 about the check valve so as to prevent it fromfreezing in the operation of the apparatus, while at the same time thehydraulic oil is cooled.

Revert gas from the two channels indicated leaves the top of the chamber17 through the valve-controlled pipe 51 and back to the compressor.

In order that the operator may know immediately the size of the cake ofDry Ice produced in the compression operation, I prefer to secure to theplate 4% mounted on the compression piston shaft 39 a rod 52. The rod52, as shown best in FIGS. 3 and 6, is connected by bracket 53 to anindicator rod 54 slidably supported within the sleeve 55. The rod 54extends over a scale 56 and with each reciprocation of the piston 38 theoperator can determine the thickness of the Dry ice block formed withinthe compression cylinder.

Operation In the operation of the apparatus, liquid CO which may berelatively warm, enters the coil 18 extending about the cone 11, whereit gives up heat to the surface of the cone 11 while at the same timemeeting the cold revert gases passing upwardly through space 17. Thechilled liquid CO is then allowed to flow, when valve 2 is open, throughpipe 22 and the expansion nozzle 23 for the forming of snow Within thecone 11, where when the piston 38 is in its forward position a pressurein the neighborhood of twenty pounds per square inch is built up. Thesnow, as it is formed while the piston is in its retracted position,drops downwardly into the compression cylinder B and is compressed bythe forward movement of the piston 33. For effective operation of theapparatus, it is important that there be a quick release of the snow,and it is found that when the piston 38 is retracted in its operationfrom the discharge end 29 of cylinder B, there is a sudden drop inpressure in the cylinder and the pressure that has been built up withinthe snow cone 11 causes a quick release of snow filling the compressionchamber for the next compression operation. Such sudden release of snowis further effected by the shape of the cone chamber 11 and by theeffect of the warm coil 13 Thus, in the reciprocation of the compressionpiston 33, it is found that there are quick or sudden releases of snowas the piston is retracted to the position shown in FIG. 4, so thatalmost immediately the piston may be moved forwardly to effect a furthercompression of the deposited snow.

The operator, by the actuation of the valve 44, may cause the piston 38to be repeatedly withdrawn and advanced to increase the size of the Dryice block to the desired thickness of, say, seven or eight inches. Theindicator rod 54 automatically shows the thickness of the block, andwhen the block is to be discharged, the operator moves valve as to causea retraction of the closure plate 30.

In order to prevent the Dry lee block from exploding or breaking up asit is suddenly released from the cylinder is, I prefer to maintain theclosure plate 39 firmly against the block at one end thereof as theblock is being ejected by piston 33, and, to this end, the restrictorvalve 37 brings about such pressure. After the block has been releasedfrom the cylinder for a few seconds, it may be released and allowed tofall into the Dry ice receptacle indicated by the numeral 57. Thereceptacle may be formed of canvas or other material for receiving theDry 6!. ice block without injury to the block. The outlet end portion ofcylinder B near the gate or closure 30 is slightly flared to facilitateremoval of the block.

in the foregoing operation, revert gases formed in the operation mayreturn while the piston is in retracted position through the boxes 48and 49 and pipe 50, and also through the plate openings 15, to chamber17. When, however, the piston 33 is in advanced position, the formerescape passages are closed oil and at this time the revert gases maypass upwardly betwezn the cylinders it) and 11 into the chamber 2S andfrom thence through passages 15 into chamber 17. While, as stated, thepiston automatically seals the entrance to the revert boxes 48 and 49,when the piston is on its forward stroke, the cold revert gas maynevertheless pass around the bottom edge of the cone and up through theadjustable slots 15 into the space 7 above the dividing flange or plate14 and such flow may be controlled by the adjustable screws 16controlling slots or passages 15. As shown best in FIGS. 4 and 5a, thelower end of the tower 11 is slightly shorter than the cylinder 1%,leaving a space through which cold revert gas may pass from the lowerportion of the tower into the restricted passage 15.

As stated earlier, the sudden release of pressure within the snow cone11 is of great importance in causing the quick release of snow from thecone and the deposit of the same within the compression cylinder B. Asthe piston 38 is advanced during the compression step toward the gate orclosure plate 3%), revert gas can no longer escape through the releaseboxes and conduit 58 into the upper cylinder chamber 17, but insteadhigh pressure is built up within the lower cylinder chamber 28 as wellas Within the chamber of cone 11, so that a relatively high pressure,say, in the neighborhood of twenty pounds, is thus built up within thecone chamber and a similar pressure within the chamber 28. Now, when thepiston 38 is retracted so as to uncover the outlet from the cone, therevert gases pass through pipe 50 into the lower pressure chamber 17 andthere is a sudden lowering of pressure within the cone chamber andwithin the chamber 28 through the release of revert gas and the flowingof the same back to chamber 17 and also by the retracting of piston 38.As a result, there is a drop in pressure within the cone chamber to,say, two or three pounds, and this sudden release of pressure, inconjunction with the other elements hereto-fore described, causes thesnow within the cone 11 to drop instantly into the compression chamberof cylinder B. In the foregoing operation, the adjustment screws 16control the restricted conduit 15 connecting chambers 28 and 17 so as tobuild up the high pressure during the forward stroke of piston 38 withinthe cone and chamber 28, and thus serve to maintain a substantialdifferential in pressure between the two chambers.

in starting the machine, it is desired to remove air from it, and thismay be accomplished by opening the closure plate 39 slightly and passingCO gas through the machine for a short period of time.

Instead of having pipes 18a and 19 passing through the sides of casingill, these pipes or tubes may be passed through the head or closureplates of cylinder 10.

It will be understood that it is also desired at times to produce snowfor commercial uses where the snow is not compacted, or compacted veryslightly. Such a product may be produced continuously in thesnow-forming tower and the snow ejected through the discharge end 29 ofthe cylinder B.

While, in the foregoing specification, I have set forth a singleembodiment of the invention in considerable detail for the purpose ofillustrating the same, it will be understood that such details ofstructure and process steps may be varied widely by those skilled in theart without departing from the spirit of my invention.

l claim:

1. in Dry Ice manufacturing apparatus, a vertical column, a rigidcone-shaped tower mounted within said column and providing a revert gasrelease chamber between it and said column, a coil within said chamberextending about said cone for circulating relatively warm liquid COabout said cone, means for releasing said circulated CO in the topportion of said tower to form snow, an angularly-related compressioncylinder communicating with the lower larger end of said tower andhaving a discharge end, movable means for closing the discharge end ofsaid cylinder, a revert gas release conduit leading from said cylinderto said gas release chamber, a compressor piston mounted in saidcylinder opposite said discharge end, means for moving said pistontoward the closed end of said cylinder for compressing snow into DryIce, for closing said conduit and for raising the pressure in saidtower, and means for retracting said piston to open said conduit and torelease said pressure in said tower whereby snow within said tower isquickly released during said return movement of the piston, said columnand cone tower providing a restricted passage therebetween oommunicatingwith a central port-ion of said cylinder for supplying a restrictedamount of revert gases to said chamber when said first-mentioned conduitis closed by said piston and said restricted passage also communicatingwith the lower portion of said tower.

2. The structure of claim 1 in which said movable closure means isadapted to engage an ice cake formed in said cylinder and includes apiston engaging the end of the ice cake and in which means are providedfor holding said piston in contact with the end of said cake as it itbeing withdrawn from the cylinder.

3. In Dry Ice manufacturing apparatus, a vertical column, a rigidcone-shaped tower mounted within said column and spaced therefrom toprovide a revert gas release chamber, a coil within said chamberextending about said cone for circulating relatively warm liquid COabout said cone, means for releasing said circulated CO in the topportion of said tower to form snow, a compression cylinder having acentral portion thereof communicating with the bottom larger end portionof said tower and said column, said cylinder having a discharge end, acompressor piston mounted for reciprocation in said cylinder toward andaway from said discharge end, movable means for closing the dischargeend of said cylinder, a revert gas release conduit providingcommunication between said cylinder and said chamber, means for movingsaid piston toward the closed end of said cylinder in the compressing ofsnow into Dry Ice thus raising the pressure in said tower and closingsaid release conduit, and means for retracting said piston to open saidrelease conduit and to release the pressure in said tower whereby snowformed with said tower is released into said cylinder, said column andcone tower providing a restricted passage therebetween communicatingwith a central portion of said cylinder for supplying a restrictedamount of revert gases to said chamber when said first-mentioned conduitis closed, said restricted passage also communicating with the lowerportion of said tower.

4. The structure of claim 3 in which threaded adjustment means areprovided for controlling flow through said restricted passage.

5. The structure of claim 3 in which said reciprocating piston isprovided at its snow-engaging end with a resilient release surface.

6. The structure of claim 5 in which said surface is formed of leather.

7. In Dry Ice manufacturing apparatus, a vertical column, a rigidcone-shaped tower mounted within said column and providing therewith arevert gas release chamber, a warming coil in said chamber and extendingabout said cone for circulating liquid CO means for releasing saidcirculating CO in the top portion of said tower to :form snow, anangularly-related compression cylinder communicating with the lower andlarger end of said tower and column and having a discharge end, acompressor piston mounted in said cylinder, movable means vfor closingthe discharge end of said cylinder, a conduit establishing communicationbetween said cylinder and chamber, means for reciprocating said pistontoward and away from the closed end of said cylinder in the compressingof snow, for closing and opening said conduit, and for raising andlowering the pressure in said tower, sai-d column and tower providingalso a restricted passage between said cylinder and chamber .forsupplying a restricted flow of revert gas to said chamber when saidconduit is closed by said piston, said restricted passage alsocommunicating with the lower portion of said tower and control means forsaid movable closure means for opening said cylinder and including apiston, fluid pressure means for reciprocating said last-mentionedpiston, a pipe supplying pressure fluid to said pressure fluid means,and a restrictor valve in said pipe for maintaining said last-mentionedpiston in contact with the Dry Ice as it is being removed from cylinder.

8. The structure of claim 7 in which an indicator rod is actuated by thecompression piston means for visually indicating the size of the Dry Iceblock formed by the compression piston.

References Cited in the file of this patent UNITED STATES PATENTS1,795,772 Goosman Mar. 19, 1931 1,870,691 Rust et al Aug. 9, 19321,920,526 Rudd Aug. 1, 1933 1,949,179 Pierce Feb. 27, 1934 1,981,676Stapp Nov. 20, 1934 1,989,873 Marcus et a1 Feb. 5, 1935 2,016,815Gilmore Oct. 8, 1935 2,025,698 Cole Dec. 24, 1935 2,145,096 Schutz Jan.24, 1939 2,151,855 Kobold Mar. 28, 1939 2,282,460 Dickey May 12, 1942FOREIGN PATENTS 433,018 Great Britain Aug. 7, 1935 678,330 France Dec.23, 1929

1. IN DRY ICE MANUFACTURING APPARATUS, A VERTICAL COLUMN, A RIGIDCONE-SHAPED TOWER MOUNTED WITHIN SAID COLUMN AND PROVIDING A REVERT GASRELEASE CHAMBER BETWEEN IT AND SAID COLUMN, A COIL WITHIN SAID CHAMBEREXTENDING ABOUT SAID CONE FOR CIRCULATING RELATIVELY WARM LIQUID CO2ABOUT SAID CONE, MEANS FOR RELEASING SAID CIRCULATED CO2 IN THE TOPPORTION OF SAID TOWER TO FORM SNOW, AN ANGULARLY-RELATED COMPRESSIONCYLINDER COMMUNICATING WITH THE LOWER LARGER END OF SAID TOWER ANDHAVING A DISCHARGE END, MOVABLE MEANS FOR CLOSING THE DISCHARGE END OFSAID CYLINDER, A REVERT GAS RELEASE CONDUIT LEADING FROM SAID CYLINDERTO SAID GAS RELEASE CHAMBER, A COMPRESSOR PISTON MOUNTED IN SAIDCYLINDER OPPOSITE SAID DISCHARGE END, MEANS FOR MOVING SAID PISTONTOWARD THE CLOSED END OF SAID CYLINDER FOR COMPRESSING SNOW INTO DRYICE, FOR CLOSING SAID CONDUIT AND FOR RAISING THE PRESSURE IN SAIDTOWER, AND MEANS FOR RETRACTING SAID PISTON TO OPEN SAID CONDUIT AND TORELEASE SAID PRESSURE IN SAID TOWER WHEREBY SNOW WITHIN SAID TOWER ISQUICOLY RELEASED DURING SAID